Basement Finishing near you

If the house is in a Special Flood Hazard Area, the basement is not simply a room to be improved. FEMA states that since 1971 the program has required that residential buildings have their lowest floor, including basement, elevated to or above the Base Flood Elevation, which FEMA describes as the elevation of surface water resulting from a flood that has a one percent chance of equaling or exceeding that level in any given year. FEMA adds that basements may be permitted below the BFE only if a community obtains an exception, and that a community must obtain an exception from FEMA before permitting the construction of residences with floodproofed basements below the Base Flood Elevation.

The rule that catches homeowners improving an existing house is substantial improvement. FEMA defines substantial improvement as any reconstruction, rehabilitation, addition or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure, or a smaller percentage if established by the community, before the start of construction. A finishing job priced under that threshold is ordinary work. One that crosses it is treated as new construction, and the building has to be brought into compliance, which for a residential structure means the lowest floor is elevated to or above the base flood level.

None of this is decided by your contractor. It is decided by the community's floodplain administrator, usually someone in the building or planning department, working from the flood insurance rate map for your address. Ask that office before design work starts, not after, and get the answer in writing.

This is the part homeowners discover too late. FEMA defines a basement for insurance purposes as any area of a building with a floor that is below ground level on all sides, and notes that rooms not fully below ground level, such as sunken living rooms, crawlspaces and the lower levels of split-level buildings, may still be considered basements because the lowest floor is below ground on all sides. Coverage under the Standard Flood Insurance Policy in that space is deliberately narrow.

FEMA's fact sheet lists what building coverage in a basement consists of: specific building items and cleanup, with items required to be connected to a power source where appropriate and installed in their functioning location. The excluded list is the one that matters when you are about to spend money finishing the space, and FEMA names basement improvements such as finished flooring, finished walls, bathroom fixtures and other built-ins among the examples of excluded items. FEMA also states that the policy does not pay for removal of non-covered items even where removing them facilitates cleanup of covered building repairs, giving the removal of carpet installed inside a basement as the example.

Radon is the reason a basement should be tested before anyone buys materials. EPA recommends fixing your home if the results of one long-term test or the average of two short-term tests show radon levels of 4 pCi/L or higher, and adds that you may also want to consider fixing if the level is between 2 and 4 pCi/L. EPA identifies active subslab suction, also called subslab depressurization, as the most common and usually the most reliable radon reduction method, which involves suction pipes inserted through the floor slab into the crushed rock or soil underneath.

Two EPA points bear directly on the order of work. First, EPA does not recommend the use of sealing alone to reduce radon, because by itself sealing has not been shown to lower radon levels significantly or consistently, so caulking the slab cracks before drywall is not a mitigation plan. Second, EPA advises that after you remodel you should retest in the lowest lived-in area, and that it is a good idea to retest at least every two years so levels remain low. A post-installation test is expected within thirty days of a system being installed.

The construction logic follows from that. Routing a vent pipe from the slab up through the house is straightforward while the framing is open and close to impossible once the ceiling is closed and the walls are painted, which is why the decision belongs at the start. EPA's guidance on building radon resistance into new houses describes the same parts you would be retrofitting: a gas-permeable layer of clean coarse gravel below the slab, plastic sheeting over it, a solid vent pipe run from the gravel layer up through the conditioned space and roof, polyurethane caulk at openings, cracks and crevices in the foundation floor and walls, and an electrical junction box in the attic for a future vent fan.

Finishing a basement creates habitable space, so a building permit is required and the space has to meet the residential code in force at your address. The figures below come from the residential code as adopted and published by the City of Seattle, which reprints the International Residential Code text that most states adopt with amendments. Use them to understand the shape of the requirement, then confirm the edition and any local amendment with your building department.

A below-grade room rarely has much glass, and the code has a view on that. Seattle's adopted residential code requires all habitable rooms to have an aggregate glazing area of not less than 8 percent of the floor area of the room, with an exception where artificial light is provided capable of producing an average illumination of 6 footcandles over the area of the room measured 30 inches above the floor. That exception is why a finished basement family room with recessed lighting and no window can still be approved, and why the lighting design is a compliance item rather than a decorating choice.

Room size is the other constraint people forget when they subdivide a basement into small rooms. The same code requires habitable rooms to have a floor area of not less than 70 square feet and to be not less than 7 feet in any horizontal dimension, with kitchens excepted from both. A narrow corridor of leftover space behind the mechanical room does not become a bedroom simply because a door is hung on it.

Older houses often have painted foundation walls, painted stair stringers and painted basement window sashes, and if the house was built before 1978 that paint is inside EPA's Renovation, Repair and Painting rule. EPA states that anyone paid to perform work that disturbs paint in housing and child-occupied facilities built before 1978 must be certified, and that the rule applies to work in houses, apartments and child-occupied facilities built before that year. Certification applies to the firm as well as to the individual renovator, including sole proprietorships.

The exemption is narrower than most homeowners assume. EPA excludes minor repair and maintenance activities that disturb six square feet or less of paint per room inside, or twenty square feet or less on the exterior, but states that window replacement and demolition of painted surfaces are always covered regardless of square footage. Enlarging a basement opening into an egress window is demolition of painted surfaces and window work at once, so it is squarely inside the rule. Ask for the firm's EPA certification and keep a copy with your project file.

The spread between two basement finishing quotes is usually structural rather than cosmetic. The variables that move it most are whether an escape opening has to be cut through the foundation and a well excavated, whether the mechanical survey forces ducts and drain lines to be relocated to hold ceiling height, whether a bathroom is being added and how far the drain has to travel to reach an existing stack, whether radon mitigation is in the scope, and whether the property sits in a flood hazard area where the floodplain administrator has a say. Ask for those five to be priced as named line items and the comparison becomes possible.

Describe the basement once on LokalMatch, including your ZIP code, the square footage you want finished, whether a bedroom or bathroom is planned, and anything you already know about flood zone status or a past radon test. Basement finishing contractors covering your area receive the request and the interested ones contact you. Pros pay for the requests they receive and homeowners pay nothing. LokalMatch does not do the work, does not price it and does not screen, rank or recommend any contractor, so verifying state licensing, insurance and references stays with you.